The present invention is directed generally to dead bolt locks and, more particularly, to dead bolt locks used on doors for accessing secure areas.
The use of dead bolts for security purposes is widespread. One example of a high security dead bolt lock is shown in U.S. Pat. No. 5,257,519 to Miller, the disclosure of which is incorporated herein by reference. Another example of these types of dead bolt mechanisms is shown in U.S. Pat. No. 4,601,504 to Wolfe, the disclosure of this patent also incorporated by reference herein. These dead bolt locks are combined with a safe lock for security purposes. The lock bolt of the safe lock provides the motive force to extend and retract the dead bolt of the dead bolt lock during operation. When using a combination type lock, a correct combination will permit retraction of the lock bolt. One drawback of such devices is that safe lock bolts and actuating mechanisms may not be well suited for long term use in this manner. In other words, they may not be designed to exert the necessary pushing or pulling force during extension and retraction of the dead bolt.
A dead bolt hold back feature has also been provided which retains the dead bolt in a retracted state. The dead bolt automatically extends as the door closes and a trigger member contacts the door strike. The extended dead bolt may be retracted from the inside of the secured area by rotation of a dead bolt knob. The aforementioned patents also disclose a life safety feature which retains the dead bolt in a retracted position so that a person inside a secured area can close the door without having the dead bolt extend. This feature enables quick exit from the secured area, however, it is not usually desirable to leave the door unlocked in this manner. On the other hand, when the life safety feature is not enabled, the above-mentioned dead bolt knobs do not provide a particularly easy manner of escape for individuals with various disabilities.
Often times, dead bolt locks on doors are combined with a second electric lock. The second lock often takes the form of an electronic access control linked to an electric door strike or lock associated with the door knob. Unlocking information provided to the access control actuates the door strike and, upon the additional retraction of any dead bolt, allows the door to be opened. It will be appreciated that this combination of a dead bolt lock and a doorknob lock makes it difficult to exit the secured area. A person leaving the secured area must use two hands to turn the doorknob and the dead bolt retraction knob simultaneously to open the door. Again, disabled individuals may have problems when trying to exit through such a door, particularly in the event of an emergency.
In view of these and other problems in this area of the lock industry, a need has developed to provide an improved dead bolt lock system.
In one general aspect, therefore, the present invention provides a dead bolt lock system for use on a door, for example, for accessing a secure area. The dead bolt lock system includes at least one security lock or access control having a movable lock member and requiring the input of correct unlocking information to change the lock from a locked to an unlocked condition. When the security lock is in an unlocked condition, a dead bolt element may be withdrawn and the door opened, for example, simply by turning a door handle on the outside of the door. In the first general aspect of this invention, a test member is provided in the dead bolt lock system, and is operatively connected to the security lock to test whether the security lock is in the locked or unlocked condition. If the security lock is unlocked, the test member can move into a space previously occupied by the movable lock member. The test member is also operatively connected to the dead bolt element such that movement of the test member in the described manner allows retraction of the dead bolt element. If the security lock is in a locked condition, then the test member is prevented from moving through the space occupied by the lock member and either the test member or other structure operatively associated with the test member prevents retraction of the dead bolt element. Preferably, this testing occurs each time the user attempts to turn the door handle.
The dead bolt lock system may be operatively coupled to more than one security lock. As an illustrative example, one security lock may be used as a primary or high security lock and one or more additional security locks may be used as secondary high or lower security locks. In each case, a locked or unlocked condition of the security lock is tested by the dead bolt lock system and, if each security lock operating in the system is found to be in an unlocked condition, the dead bolt system may be operated by the door handle to withdraw the dead bolt and open the door. The security locks may specifically include lock bolts, such as linearly extendable bolts or swing bolts, and may comprise mechanical, electrical or electro-mechanical locks. For example, in the case of locks having linearly extendable bolts, the lock bolt will block the test member when extended and will not block the test member when retracted. In the case of swing bolts, the swing bolt will block the test member when in a locked condition, but may be forced into a retracted position by the test member when in an unlocked condition. Other types of security locks and lock bolts are also within the scope of this invention. A torque override clutch is preferably connected to the door handle to prevent transmission of excessive force to the internal components of the dead bolt lock system when the system is locked and the door handle is being rotated with excessive torque.
Stated generally, the dead bolt lock can provide different levels of security and monitoring capability. By providing at least one primary lock and one secondary lock, the dead bolt lock system can have at least two levels of control or security. The primary lock in combination with the secondary lock may be used for nighttime control and the secondary lock may be used alone for daytime control. That is, the primary lock or high security lock can remain unlocked during the day and entry into the secured area can be controlled by the operation of one or more high or lower security lock devices. Another type of security lock device which may be optionally incorporated into the system is referred to herein as an access control device. This device includes an electrically actuated movable lock member which normally blocks movement of a test member similarly associated with retraction of the dead bolt element. If the movable lock member is actuated through the input of proper unlocking information, then the test member will be able to move through the space previously occupied by the movable lock member. Due to the movement of the test member in this manner, the dead bolt element will retract, for example, as the operator turns the door handle. Preferably, the access control device comprises a solenoid having an electrically actuated movable member, such as a reciprocating piston element. This device may be controlled, for example, simply by one or more push button switches or by higher security controls like card readers, retinal scanners, voice identifiers or fingerprint identifiers.
An escape lever is also provided on the interior side of the lock system and may be operated by either pushing or pulling on the lever. This actuating movement is preferably a pushing movement toward the door or a pulling movement away from the door, but may also be a sideward or up and down pushing or pulling movement. This overrides all locking mechanisms associated with the system, except for a relock feature to be discussed below, to allow quick escape from the secure area. The lever is configured to be easily operated by persons having various disabilities.
Preferably, the inventive dead bolt lock also includes one or more blocking elements positioned to receive a force applied to an end face of the dead bolt, usually during an unauthorized entry attempt. This prevents damage to the dead bolt lock system components. The blocking element may be automatically disengaged when the dead bolt is retracted during normal operation.
The preferred dead bolt lock system also includes a unique dead bolt hold back feature employing a pivoting member disposed between a spring biased trigger member and the dead bolt element. For purposes of carrying out this feature, the dead bolt element is normally spring biased in an extended position. The pivoting member cooperates with the dead bolt element to maintain the dead bolt element in a retracted position when the door is open. The trigger automatically actuates to allow the dead bolt element to extend upon contact with a door strike or the like.
As another feature of this invention, a night latch or lock down feature is provided and prevents operation of the dead bolt lock system regardless of whether the security locks are inputted with correct unlocking information. Even when the night latch feature is enabled, however, the escape lever may be operated to allow a person to leave the secure area.
As another optional feature, the dead bolt lock system may also include a lock override mechanism. This mechanism allows each of the security locks, access controls and lock down feature to be overridden from the outside of the door through the use of an appropriate key. This key may be inserted and rotated to withdraw the dead bolt without the necessity of inputting the correct unlocking information into the security locks and/or access control.
The dead bolt lock system also includes one or more interior housing covers referred to in the industry generally as locked-on-by-combination covers, but operating in a unique manner in the present invention. The covers are removable only when the dead bolt is retracted through normal operation and the outside door handle is in a rotated position. This helps prevent unauthorized access to the interior of the lock system.
Also in connection with the housing covers, relock mechanisms may be provided to ensure that the dead bolt lock system cannot be operated after removal of the housing covers. Specifically, if the housing covers are removed, the relock mechanism automatically shifts into a position that prevents operation of the dead bolt retracting structure. This provides an additional level of security against unauthorized access through the dead bolt lock system of this invention.
Electrical sensing devices, such as microswitches, can be provided to sense, monitor, audit or even control various lock operations. The most basic of these may be to indicate on a control panel, for example, whether the dead lock bolt is in a retracted or extended position. Similarly, indicator switches can be provided to detect whether the other lock bolts combined with the dead bolt are in retracted or extended positions. It is also contemplated that the indicator switches can be wired in series, for example, to provide one overall indication of a locked or unlocked condition.
The various features, assemblies and systems described above can be used in combination with each other or separately depending on the particular application of the dead bolt lock system. In addition, various mechanical or electrical component designs and configurations could be used within the spirit and scope of the inventive concepts.
The inventive dead bolt lock provides significant advantages over prior dead bolt locks. First, a dead bolt lock system of this invention can accept any conventional safe lock, e.g., a combination lock, mechanical lock or electro-mechanical lock, manufactured to a standard specification or, in other words, with a standard footprint. More specifically, one or more housings of the dead bolt lock system accept locks having a standard footprint, as is often required by government specifications. Moreover, the dead bolt lock system functions with a variety of security lock devices, including those using standard lock bolts which extend and retract linearly from the lock casing or locks using swing type bolts which pivot from the lock casing, for example, with a spring bias. In any case, however, the lock member or bolt does not apply or receive significant pushing or pulling force during operation of the dead bolt lock system. Because housing or support structure may be situated adjacent the lock member or bolt, and because of the torque override clutch, the system prevents significant side loads on the lock members or bolts. Security lock bolts generally are subjected to only side loads, either from the lock bolt testers as described above or from an unauthorized entry attempt. As another advantage of the invention, the security locks and access controls may be eliminated and the system will still function as a dead bolt passage set. In this type of use, for example, the lock down feature may still be a functional part of the system.